Many types of input devices may be used to provide input to computing devices, such as buttons or keys, mice, trackballs, joysticks, touch screens and the like. Touch screens, in particular, are becoming increasingly popular because of their ease and versatility of operation. Typically touch screens on interfaces can include a touch sensor panel, which may be a clear panel with a touch-sensitive surface, and a display device that can be positioned behind the panel so that the touch-sensitive surface substantially covers the viewable area of the display device. Touch screens allow a user to provide various types of input to the computing device by touching the touch sensor panel using a finger, stylus, or other object at a location dictated by a user interface being displayed by the display device. In general, touch screens can recognize a touch event and the position of the touch event on the touch sensor panel, and the computing system can then interpret the touch event in accordance with the display appearing at the time of the touch event, and thereafter can perform one or more actions based on the touch event.
Some input devices, such as styli, allow a user to use the input device as a pen or pencil and “write” on the touch screen or other input-ready display. Often the output of a stylus, as displayed on the screen, may be varied. For example, the color or line thickness corresponding to the input of the stylus may be varied. These variations are typically done by the computing device and thus the user may not know what the output of the input device will be until the output is displayed on the screen.